To address the issues of long leaching time and high consumption of hydrochloric acid in the conventional hydrochloric acid leaching method for neodymium-iron-boron (NdFeB) waste, the ultrasonic-enhanced hydrochloric acid solubilization method was studied for the leaching of rare earths from it. The effects of ultrasonic power, hydrochloric acid concentration, temperature, liquid volume to solid mass ratio, leaching time, particle size and other factors on the leaching rate of rare earths were investigated, and the optimal leaching parameters were determined. The results show that ultrasonic assistance significantly enhances the leaching process. Under the optimal conditions of ultrasonic power of 60 W, hydrochloric acid concentration of 2 mol/L, temperature of 85 ℃, liquid volume to solid mass ratio of 10 mL/1 g, leaching time of 105 min, and particle size of -0.074 mm, the rare earth leaching rate reaches 97.94%, which is 8 percentage points higher than that of the conventional hydrochloric acid leaching method under its best conditions. The method is an efficient and feasible green process for rare earth recovery and provides a new approach for the resource utilization of NdFeB waste.
| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |